Magnetic flooring system adhesive composition

ABSTRACT

A liquid adhesive coating composition that cures into a solid form, used to non-permanently adhere interior floor or wall coverings to substrate floor or wall surfaces respectively, includes a polymer incorporating iron or other paramagnetic, superparamagnetic, ferromagnetic, or ferrimagnetic ingredients, that becomes permanently adhered to the substrate as it cures, and thereafter provides a low-tack adhesive surface that is also magnetically attractive, upon which magnetized floor or wall coverings including certain types of carpet, linoleum, vinyl, wallpaper, and other types of magnetically-backed coverings can be subsequently installed. The combined low-tack adhesive and magnetic adhesion qualities of the cured composition of the invention allow for the magnetically-backed floor or wall coverings to be sufficiently well adhered to the surface of the cured adhesive composition to remain in place during normal usage while retaining the ability for the coverings to be subsequently removed, repositioned or replaced without damaging the respective coverings, adhesive coating composition layer, or substrate.

FIELD OF THE INVENTION

The present invention relates to magnets and adhesive coatingcompositions used to adhere interior floor and wall coverings tosubstrate surfaces, particularly flexible coverings provided withmagnetic backing that normally come in the form of tiles or rolls suchas certain kinds of linoleum, vinyl, carpet and wallpaper.

BACKGROUND OF THE INVENTION

Modern interior rigid floor coverings evolved from slate, stone,ceramic, clay and other types of tiles, loosely or tightly placed, orgrouted, onto dirt or clay substrates, or placed onto or adhered to woodor cementitious substrates using cementitious liquids and pastes thatdry or otherwise cure into solid form. These early types of rigidflooring are still commonly used. Modern flooring adhesives stillinclude these above types but there has generally been a shift towardusing polymers, either alone or in combination with cementitiousmaterials, to adhere rigid floor coverings to the respective substratefloor. Rigid composite laminate flooring systems have also become quitepopular in recent years and are a modern example of tightly placedinterlocking pieces that are not normally bound to the substrate floorwith adhesives.

The various types of rigid floor coverings remain important but less sothan in earlier times. Flexible floor coverings now form a large part ofthe flooring market. Rigid wall coverings evolved similarly to floorcoverings, with ceramic tiles often used in kitchens and bathrooms beinga common modern example of a rigid wall covering system.

Early interior flexible floor coverings that could be rolled or bentincludes animal skins, mats or carpets made from vegetation, animal hairsuch as wool, and other textiles, fibrous materials and fabrics that aremade into various woven and non-woven types. There is a wide range ofcarpet types and styles that have evolved along different paths invarious parts of the world. Carpets, linoleum, vinyl and flexiblelaminate flooring, now often made from synthetic polymers, have evolvedfrom the earlier types.

Interior flexible floor coverings are loosely placed or adhered tosubstrates using tacks, nails, screws and/or other types of mechanicalfasteners. They are also able to be adhered to substrates using liquidor paste adhesives that dry or otherwise cure into rigid or flexible(elastomeric) binding layers, with or without using mechanical fasters.Cementitious liquids and pastes are generally not used to adhereflexible floor coverings to their respective substrates. Presently,flexible floor coverings that employ adhesives comprise non-cementitiousadhesive polymers, often in combination with mechanical fasteners. Inthe case of carpeting and some other flooring types, various underlayssuch as flexible foam sheets can be and are often sandwiched between thecarpet and substrate floor.

Many of the flexible floor coverings described above can also be used aswall coverings. However, the most common type of interior wall coveringis paint, with wallpaper also being a very important type. The wallsubstrates in present use comprise stone, brick, concrete, concretemasonry blocks and wooden boards and panels as well as plaster amongearlier types although modern interior wall systems are largely builtusing gypsum wallboards that have the joints made smooth and ready toaccept one or more coats of paint, wallpaper or other type of covering.Various types of paints, varnishes and other finishes are applied as aliquid with brushes, rollers or sprayers, then dry or otherwise cureinto a solid finished coating. Wallpapers are normally adhered usingnon-cementitious liquid adhesives that similarly dry or cure into asolid form. Wallpapers are often installed using starch-based adhesives.Vinyl peel-and-stick wallpapers are available but are less common thanconventional wallpapers that require a separate adhesive layer.

For interior floors and walls, flexible coverings were and are stilloften used on top of either rigid or flexible coverings. For example, abearskin can be hung on a painted wall or loosely laid on top of a mator carpet that, in an example of further layering, has said mat orcarpet installed on a stone tile floor where the stone tiles have beengrouted and adhered to a wood or concrete floor substrate using acementitious compound.

Flexible coverings are typically delivered and installed from rolls,packages of flat strips or bundles or boxes of tiles.

Paints and other types of coating compounds that are applied as a liquidand dry or cure into solid form and become permanently adhered to wallsubstrates are also used on floor substrates, albeit not as commonly asthey are used on walls. In the case of flooring, the most common caseswhere floors are painted or coated using a liquid application are incommercial and industrial flooring sectors, usually on concrete or steelfloor substrates. Ship floors, usually referred to as decks, arenormally covered in this manner.

It is quite evident from this above description that there is often adesire to have floor or wall coverings, except in the case of paintwhere it is usually relatively easily recoated without needing to removethe earlier paint covering, not be permanently adhered to the respectivefloor or wall substrates. This is especially preferred in the case ofmany flexible covering applications. The desire for non-permanentadhesion is less common for rigid flooring types although there arepeople who would prefer to be able to change rigid floor tiles toreplace damaged ones or change the style from time to time withoutneeding to engage in difficult and costly removal and replacementprocedures that usually damages or destroys the covering being removed,adhesive layer and/or substrate.

Floor and wall adhesives are normally considered to be permanent whichmeans that they are only used once to fix a covering onto a respectivesubstrate. The adhesive layer is destroyed and needs to be replaced whenan existing covering is removed and a new covering is installed. Thecovering is also normally destroyed and replaced with a new one. Thisremoval and replacement does not normally occur in the case of paint.Where paint is used as a covering, the existing paint covering simplyhas one or more additional layers of paint applied on top of theexisting paint. This is not the usual case for other types of floor orwall coverings although does occur in some situations. For example,wallpaper can have another layer adhered overtop of an existing one butthis is not considered to be the best approach. The better practice,albeit more costly and difficult, is to strip out the old wallpaper andadhesive layer then apply a fresh adhesive with the new wallpaper.Non-permanent adhesives are generally not very effective for use withcarpets and other floor or wall coverings inasmuch as they tend todegrade over time and/or with repeated use.

For installations of wall-to-wall carpet, it is often preferable to gluethe carpet down, especially for large area installations. Forinstallations of vinyl tiles, as is the case for most types of tileflooring, whether flexible or rigid types, it is generally considered arequirement that the tiles must be bound to the substrate using anadhesive. Due to the large areas often involved, such adhesives need tobe cost-effective on an installed cost per unit area calculation basis.Where an adhesive layer needs to be replaced, the costs are not normallyconsidered to be prohibitive.

Magnetic adhesion systems for attaching wall and floor coverings torespective wall and floor substrates have gained limited marketacceptance in recent years. They tend to be rather costly as compared totraditional adhesives. However, the benefit of being able to remove,reposition and/or replace the coverings without damaging them, thesubstrate or the magnetically attractive layer of the substrate has beenshown to be of considerable benefit.

SUMMARY OF THE INVENTION

A liquid adhesive coating composition that cures into a solid form, usedto non-permanently adhere interior floor or wall coverings to substratefloor or wall surfaces respectively, comprises a polymer incorporatingiron or other paramagnetic, superparamagnetic, ferromagnetic orferrimagnetic ingredients, that becomes permanently adhered to thesubstrate as it cures, and thereafter provides a low-tack adhesivesurface that is also magnetically attractive, upon which magnetizedfloor or wall coverings including certain types of carpet, linoleum,vinyl, wallpaper and other types of magnetically-backed coverings can besubsequently installed. The combined low-tack adhesive and magneticattraction qualities of the cured composition of the invention allow forsaid magnetically-backed floor or wall coverings to be sufficiently welladhered to the surface of said cured adhesive composition, to remain inplace during normal usage while retaining the ability for said coveringsto be subsequently removed, repositioned or replaced without damagingthe respective coverings, cured adhesive coating composition orsubstrate.

The combined magnetic attractiveness and low-tack adhesive effects ofthe repositionable floor or wall coverings installed upon the respectivesubstrates coated with the composition of the present invention can bevaried by varying either or both the magnetic attractiveness and thenon-permanent chemical adhesive aspects, as further described in thedetailed description herein.

The composition of the invention includes embodiments in which theadhesive compound cures in the form of elastomeric foam, with the foamcreated by means of a secondary chemical reaction as the compositioncures from a liquid into solid form. Said elastomeric foam also hascombined magnetic attractiveness and low-tack adhesive qualities withadditional cushioning and sound abatement qualities.

The composition of the invention includes embodiments in which theadhesive composition cures at ambient temperatures or at elevatedtemperatures. Exemplary embodiments include adhesive compounds that areapplied to substrate floors or walls as liquids as well as adhesivecompounds that can be manufactured in roll or sheet form, laid onto thesubstrate floor or walls and subsequently heated to bind them to therespective substrates.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present invention. The terminology includesthe words specifically mentioned, derivatives thereof and words ofsimilar import. The embodiments illustrated below are not intended to beexhaustive or to limit the invention to the precise form disclosed.These embodiments are chosen and described to best explain the principleof the invention and its application and practical use and to enableothers skilled in the art to best utilize the invention.

Reference herein to “one embodiment” or “an embodiment” means that aparticular feature, structure, or characteristic described in connectionwith the embodiment can be included in at least one embodiment of theinvention. The appearances of the phrase “in one embodiment” in variousplaces in the specification are not necessarily all referring to thesame embodiment, nor are separate or alternative embodiments necessarilymutually exclusive of other embodiments. The same applies to the term“implementation.”

As used in this application, the word “exemplary” is used herein to meanserving as an example, instance, or illustration. Any aspect or designdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects or designs. Rather, use ofthe word exemplary is intended to present concepts in a concretefashion.

Additionally, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or”. That is, unless specified otherwise, or clearfrom context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A; X employs B; or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. In addition, the articles “a” and “an” as usedin this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromcontext to be directed to a singular form.

Unless explicitly stated otherwise, each numerical value and rangeshould be interpreted as being approximate as if the word “about” or“approximately” preceded the value of the value or range.

It should be understood that the steps of the exemplary methods setforth herein are not necessarily required to be performed in the orderdescribed, and the order of the steps of such methods should beunderstood to be merely exemplary. Likewise, additional steps may beincluded in such methods, and certain steps may be omitted or combined,in methods consistent with various embodiments of the present invention.

Although the elements in the following method claims, if any, arerecited in a particular sequence with corresponding labeling, unless theclaim recitations otherwise imply a particular sequence for implementingsome or all of those elements, those elements are not necessarilyintended to be limited to being implemented in that particular sequence.

The prior art is replete with elastomeric adhesives including silicones,latex and other types of rubber-based ones, elastomeric polyurethanes,etcetera. Attempting to fully list or describe numerous suitable onesthat can be usefully combined with magnetic and/or magnetizableparticles in any amount of detail would be a rather cumbersome andexhaustive undertaking. The preferred approach taken here to make it amore manageable task is to narrow down to the currently most preferredones by focusing on some preferred attributes.

At its broadest, the composition of the invention comprises a polymericadhesive with magnetic and/or magnetizable particles dispersedthroughout that permanently adheres to a substrate as the adhesive curesinto a solid form. The cured composition has relatively high elasticityand the exposed surface of the cured composition has a low-tack adhesivequality.

Exemplary elastomeric adhesive coating compositions of the presentinvention can be of a single component or of a two componentconfiguration (which can also be referred to as a two part configurationor two part composition) with the magnetic and/or magnetizable particlesincorporated into one or both of the components or, in the alternative,able to be added in the field and mixed into one of the components priorto mixing in the other component or, in the further alternative, able tobe added in the field and mixed in after the two components have firstbeen mixed together.

Exemplary embodiments of the elastomeric adhesive coating compositionhave low enough viscosity in both of the respective components such thata maximum amount of magnetic and/or magnetizable particles can beincorporated into the composition of the present invention while keepingthe effort required to mix the components together to a minimum, belowabout 250 cPs dynamic viscosity at about 25 degrees Celsius or about 77degrees Fahrenheit (prior to adding magnetic and/or magnetizableparticles). Mixing in of the magnetic and/or magnetizable particles canbe carried out using simple hand tools such as a stirring stick or anelectric drill with a mixing paddle. It is not and should not benecessary to use industrial paint shakers or other bulky or costlyequipment to mix the composition in a field application.

Exemplary embodiments of the composition are not dependent onatmospheric moisture for curing although moisture cured adhesives can beused within the scope of the present invention. Exemplary embodiments ofthe invention also include liquid or solid single component adhesiveswith magnetic and/or magnetizable particles incorporated into theadhesive. While single part solvent-based, latex and acrylic liquidcompositions are less desirable than two component liquid compositionsnotwithstanding the convenience of not having to mix two componentcompositions in the correct proportions, such adhesives are still withinthe scope of the present invention.

Exemplary embodiments include non-liquid or solid adhesive compoundsthat are adhesive compounds with magnetic and/or magnetizable particlesincorporated into the adhesive that can be manufactured in solid formsuch as rolls or sheets, laid onto the substrate floor or walls andsubsequently heated or pressed to bind them to the respective substratefloors or walls. Such adhesives can be hot-melt type adhesives or have apressure-sensitive adhesive aspect respectively. Hot-melt adhesives aresolid and have good strength at temperatures below about 50 degreesCelsius (about 120 degrees Fahrenheit) and typically melt attemperatures above about 200 degrees Celsius (about 400 degreesFahrenheit). Such adhesives begin to re-solidify at temperatures belowabout 150 degrees Celsius (about 300 degrees Fahrenheit).

Moisture-cure, single-component adhesives are generally slow curing andhave no mechanism for controlling the cure rate during the applicationprocess. The cure rate is also dependent on ambient temperature andhumidity. Air dry adhesives usually contain solvents to control the cureprocess. Thus, for such air dry adhesives, the cure rate is dependent ontemperature and humidity. While two-component adhesives are contemplatedas the preferred adhesive component of the present invention,single-component adhesives, including those discussed above, areintended to be covered by the present invention, with the two-componentsof the adhesive described in detail below being substituted with thesingle-component adhesive.

Elimination of solvents that are generally considered undesirable,especially in the case of indoor applications, is becoming a moreimportant consideration for environmental reasons. Latex, vinyl andacrylic adhesives are quite popular although, once cured, tend to havepoorer longevity and less resistance to moisture than the exemplary twocomponent systems. The magnetic and/or magnetizable particles can beeither pre-mixed into these components or mixed into the compositions inthe field.

Minimizing costs is a key motivator, as is normal for commercialproducts being brought to market. Conversely, maximizing storage orshelf life of the unmixed components to at least one year, preferably toten years or longer is advantageous. The unmixed components of theexemplary embodiments of the present invention are expected to have longstorage or shelf life.

Another motivator is to move toward using renewable ingredients and havethe compositions able to be produced in the most sustainable mannerpossible. There are benefits such as LEEDS™ certifications which havebecome important in recent years for residential and commercial buildingprojects.

An open time, working time or pot life, defined as the time after mixingwithin which the mixed composition can be applied before the compositionhas cured to the extent that the composition is no longer workable, istypically in the range of 10 to 30 minutes with full cure (to at leastabout 90% of final hardness) within about 24 hours. The exemplaryembodiments of the invention can optionally include the use of curingadditives that are used to set the cure rate, both the open time and thetime to full cure.

The packaged quantities can be kept in the range of 2 to 15 liters (0.5to 4 U.S. Gallons) mixed quantity for each packaged two part “unit”,with the unit weight, including the magnetic and/or magnetizableparticles, kept below the maximum weight a person can safely handle forall manual applications, less than 45 kg (100 pounds). This maximumweight includes the addition of the magnetic and/or magnetizableparticles. A notable exception would be in the case of large sprayapplication systems in which the components can also be packaged inlarge quantities.

Two-component urethane (polyurethane) adhesives are well known and arewidely used as structural adhesives. Polyurethane adhesives, in general,as compared to other classes of adhesives, are often chosen based ontheir outstanding flexibility, bond strength, shock and impactresistance, durability, chemical inertness and other desirableproperties. Such adhesives are usually comprised of two components, withone component comprising an isocyanate-terminated compound having atleast two reactive isocyanate groups, and a second component comprisinga hydroxyl-terminated compound having at least two reactive hydroxylgroups.

The vast majority of prior art adhesives, including these abovedescribed adhesives, are permanent adhesives, which means that onceapplied and cured, the adhesives are not able to be reused. Attempts toreposition articles adhered with permanent adhesives normally result indamage to or destruction of the adhesive and often the articles beingadhered to.

Pressure-sensitive adhesives are adhesives that bond when pressure isapplied to marry the adhesive with the adhered. No solvent, water orheat is needed to activate the adhesive. Most pressure-sensitiveadhesives are also of the permanent type, although this class ofadhesives includes many non-permanent adhesives that maintain theiradhesive qualities sufficiently well that articles such as adhesive tapestrips can be re-applied or repositioned. Such non-permanent orrepositionable adhesives form a relatively small subset of the generalcategory of adhesives.

Some adhesives are intended to exhibit different adhesive qualities atdifferent times. For instance, it is known in the art that certaincompositions can be partially cured at room temperature underatmospheric conditions in a rapid fashion to give a partially curedcomposition within a few minutes, which exhibits properties similar tothose of pressure-sensitive adhesives having excellent tack, shear andpeel strengths. Development of full strength occurs over a longer timeframe in such adhesives. Where a composition comprising a blockedisocyanate prepolymer obtained by the reaction of a poly(alkylene oxide)polyol and a diol or triol with a diisocyanate in equivalent ratio oftwo isocyanate groups per hydroxyl group followed by capping theremaining isocyanate groups with phenolic blocking agents such as phenolis mixed with a polyamine, a flexible structural adhesive composition isobtained which exhibits a long open time with excellent tack and peelstrength prior to full gelation or cure.

An exemplary pressure-sensitive adhesive comprises the reaction productof at least one alkyl acrylate liquid polymer containing both terminaland random hydroxyl functionality, and at least one prepolymer of apolyester glycol or a polyalkylene ether glycol with an excess amount ofan aromatic diisocyanate. Such an adhesive has desirable propertiesincluding excellent rolling ball tack, peel adhesion and shear adhesion.However, such adhesives tend to be permanent adhesives.

Repositionable or non-permanent adhesives of interest include exemplaryadhesives that comprise tacky, elastomeric copolymer hollow or solidmicrospheres and macromonomer-containing binder copolymers. Theseadhesives may further comprise at least one acrylate ester. Thesemicrosphere-type repositionable adhesives tend to be rather costlycompared to other pressure-sensitive adhesives known in the art.

Combining magnetic and/or magnetizable particles with any such adhesiveyields interesting and useful embodiments of the present invention,although there are other embodiments, which also tend to be less costly,prepared from two component polyurethane adhesives that have more of thepreferred attributes described earlier in this description. Specificexamples of exemplary embodiments of the invention are provided below interms of, among other things, chemical composition, desirable and/orfavorable attributes and relevant properties.

EXAMPLE 1

In a two-part combination, low-tack polyurethane adhesive coatingcompound of the invention, a first component of the inventive adhesiveis a polymerizable isocyanate, which includes any isocyanate that isknown in the polyurethane art to polymerize with hydroxyl-containingcompounds. An exemplary isocyanate is one containing4,4′-diphenylmethane diisocyanate (MDI) alone or in combination with its2,2′-isomer, 2,-4′-isomer and/or, polymethane polyphenyl isocyanate. Inan exemplary embodiment, the MDI comprises between about 30% and about60% by weight of the combination. The product currently made by DowChemical called PAPI-27™ is an exemplary polymerizable isocyanate. Thisisocyanate combination is often referred to in the art as “polymericMDI”. It is also commonly classified as an aromatic type, in contrastwith various ones of an aliphatic type known in the art that arenormally more costly but have some desirable properties such as beingmuch less likely to change color when exposed to ultra-violet radiation.

A second component of this two-part combination, low-tack polyurethaneadhesive coating compound comprises a certain class of polyols known asglycerides or acylglycerols, which are esters formed between glyceroland one or more fatty acids. Glycerides are generally found in plantoils and animal fats. glycerides can also, in some cases, be producedsynthetically from a range of starting materials. In exemplaryembodiments, the glycerides are vegetable oils. In further exemplaryembodiments, the glycerides are castor oil. Castor oil, a natural andrenewable product, is a fatty acid triglyceride which on averagecontains 2.7 secondary OH-groups per molecule, the fatty acid beingprimarily ricinoleic acid. This polyol or glyceride, which includes somepreferred modifications as will be described in detail below, will bereferred to herein as “modified castor oil”.

The Example 1 mixture of the first component and the second component,prior to the inclusion of the magnetic and/or magnetizable particles,where the first component is the polymeric MDI described above and thesecond component is modified castor oil described above and insubsequent paragraphs, is in the ratio second component:first componentof 70:30 parts by weight or 3:1 parts by volume. This is a purposelyderived set of ratios because round number ratios are more easilymeasured in the field, especially by volume, than are fractional ratios.Standard mixing pails used in the coating and painting trades often comewith pre-printed markings showing, for example, 1:1, 2:1, 3:1 and 4:1volumetric ratios.

The 3:1 volumetric ratio is a preferred one since there is enough liquidvolume in the second component (modified castor oil in this Example 1)to accommodate a substantial amount of the magnetic and/or magnetizableparticles (as will be described in detail in a later part of thisdescription) in the mixture where these particles are either pre-blendedinto the second component at the factory, mixed into the secondcomponent in the field or mixed into the mixture of the first and secondcomponents. There can however be a wide range of ratios, rangingpractically from 1:1 to 4:1 (volumetric) and they do not need to be inround number or integer increments, notwithstanding the statedpreferences. Pre-polymerizing some of the castor oil or otheringredients into the first component, including adding varying amountsof active or passive ingredients to either the first or second componentor to both components are among techniques that can be used to adjusttwo component formulations to meet a specific volumetric and/orgravimetric ratio of the components. There are many methods known in theart since many two component formulations need to be designed to aspecific ratio to match to equipment designs that are normally set inspecific volumetric ratios, the most common ratios being 1:1, 1.5:1,2:1, 3:1 and 4:1 parts by volume or PBV.

The magnetic and/or magnetizable particles used in the composition ofthe invention are preferably added to the castor oil component inExample 1 for a number of reasons. Firstly, it is considered goodpractice to not add anything to the isocyanate component since it muchmore reactive than the castor oil component and easily contaminated. Theisocyanate component is normally packaged with a nitrogen blanket in asealed container, said non-reactive nitrogen displacing any atmosphericmoisture or oxygen. Secondly, the castor oil component, being mainlyoil, is easier to mix the magnetic and/or magnetizable particles intoand creates a smoother and more easily stirred mixture. Engineering thecomposition with the relatively large oil component makes it relativelyeasy to get all of the needed magnetic and/or magnetizable particlesmixed into the adhesive coating compound of the invention withoutincreasing the viscosity too much. Thirdly, mixing the magnetic and/ormagnetizable particles into the second component does not initiate anychemical reactions. This is beneficial in that one can take as much timeas needed to mix in the magnetic and/or magnetizable particles untilthey are well dispersed without using up any of the working time (potlife). If the magnetic and/or magnetizable particles are subsequentlyadded to the mixture of the first and second components, the time takento get the magnetic and/or magnetizable particles mixed and disbursedreduces the remaining working time accordingly inasmuch as the mixtureof the first and second components begins reacting immediately as theycome into contact with each other. It takes relatively little time formixing the first component in after the magnetic and/or magnetizableparticles are already dispersed into the second component.

The pricing and availability of castor oil has historically proven to berather volatile. Therefore, ring-opening products of epoxidized fattyacid esters with aliphatic alcohols having a functionality from 1 to 10can be used. Renewable starting materials include: epoxidized soybeanoil having an epoxide number from 5.8 to 6.5, epoxidized sunflower seedoil having an epoxide number from 5.6 to 6.6, epoxidized linseed oilhaving an epoxide number from 8.2 to 8.6 and epoxidized train oil havingan epoxide number from 6.3 to 6.7. The epoxidized triglycerides may besubjected to complete ring opening with polyhydric or monohydricalcohols or even to partial ring opening. Partial ring opening resultsin the formation of modified triglycerides containing on average epoxideand hydroxyl groups and also other groups. This sub-group ofring-opening products of epoxidized triglycerides comprises compoundswhich are readily available and can be produced in a wide range ofvariation.

Various epoxidized triglycerides of agricultural origin, in other words,from vegetable or animal origin, may be used as starting materials forproducing the ring-opening products, with the main requirement beingthat a substantial portion of epoxide groups should be present. Forexample, epoxidized triglycerides containing between about 2% and about10% by weight of epoxide oxygen are suitable. Products having an epoxideoxygen content between about 3% and about 5% by weight are particularlysuitable for certain applications. This epoxide oxygen content may beadjusted by starting out from triglycerides having a relatively low zoiodine number and subjecting them to thorough epoxidation or by startingout from triglycerides having a high iodine number and only partlyreacting them to form epoxides.

Another group of products suitable for adhesive applications is based onepoxidized triglycerides having an epoxide oxygen content between about4% and about 8.5%. Products such as these can also be produced from thefollowing fats and oils (in order of increasing initial iodine number):beef tallow, palm oil, lard, castor oil, peanut oil, rapeseed oil andcottonseed oil.

Starting with raw castor oil, often classified in the art as No. 1crude, some relatively simple modifications are made to the raw oil,sometimes after any remaining solids are filtered out, to produce aparticularly preferred embodiment of the present invention. Suchmodifications can include the optional addition of pigments in theamount of about 2% by weight such as titanium dioxide (white) and blackiron oxide. The black iron oxide also has magnetic properties althoughat an insignificant level given such small quantities as this 2%. Theoil needs to be free of moisture which can be achieved by heating todrive off the excess moisture, adding a dessicant, an example one beingsynthetic zeolite, in the amount of about 1% by weight, or both, heatingfollowed by such an addition.

In certain exemplary embodiments, a blowing or foaming agent may beincorporated. These blowing or foaming agents react with the isocyanateto produce carbon dioxide. A small amount of water can be added, or analcohol. Various blowing agents can be used alone or in combination toproduce different qualities and amounts of foaming while curing. Cellsize and structure (closed cell, open cell, size distribution, etc.) canbe thus influenced.

Surfactants and/or emulsifiers can also be used to modify the castoroil. Plasticizers such as plasticizing oils can be optionally added.Solvents can also be employed. Electrically conductive material can beadded, notwithstanding that various among the preferred magnetic and/ormagnetizable particles are electrically conductive. Metallic and/ornon-metallic flakes can be added for visual effects. Materials to resistthe effects of ultra-violet radiation and anti-oxidants can also beincorporated.

Further materials such as abrasives, carbonates or boron components orzo other fire resistance enhancing additives can be included. Additivesfor higher absorption resistance, strength-enhancing cellulose or glassfiber can also be used as can various fillers. Toxins and anti-bacterialadditives can be added to prevent bacterial growth or other forms offouling.

Although the Example 1 composition of the invention will cure at ambienttemperature to at least about 90% of final hardness within about 24 to36 hours, in an exemplary embodiment, an accelerator can be added to thecomposition to speed curing in various instances. These acceleratorsinclude tertiary amines, for example dimethylethanolamine (DMEA), or anorganometallic compound, for example, dibutyltindilaurate (DBTL) ordioctyltindilaurate (DOTL). Various accelerators can be used alone or incombination to effect different cure rates at different parts of thecuring cycle. Such accelerators can also be selected to bias orpreferentially cure different aspects at different rates. For example,there are ones that will speed the primary curing while not speeding upthe secondary foaming reaction, or vice versa.

Exemplary magnetic and/or magnetizable particles are selected fromparamagnetic, superparamagnetic, ferromagnetic and/or ferrimagneticsubstances, in particular selected from the group consisting of iron,cobalt, nickel, gadolinium, dysprosium, iron-nickel alloy (permalloy),iron (II,III) oxide (magnetite), iron (III) oxide (hematite),ferrosilicon, mixed iron oxides, mixed iron oxides with other metaloxides from the transition elements group like iron-nickel oxides, andcombinations thereof.

The magnetic or magnetizable particles are granular or in the form ofpowders, flakes or filings or combinations thereof. The preferredparticles are granular or in the form of powders and have an averagediameter of between about 100 nm to 1000 micrometers, in particularbetween about 1 micrometer and about 350 micrometers. A lower thresholddiameter of greater than about 100 nm is is selected due to viscositylimitations, improved magnetic properties and, currently, costconsiderations.

Particles smaller than 100 nm tend to increase viscosity too quicklysuch that it becomes difficult to mix in enough of them to achievesufficient density of magnetic and/or magnetizable particles in a curedadhesive coating composition of the invention to meet the minimummagnetic attractiveness requirements for floor or wall coverings. It isalso well known that for many magnetic and/or magnetizable materials,coarser particles with larger grain size generally provide for increasedmagnetic permeability, an advantage of using larger particle sizes.Costs currently also tend to decrease for larger particle sizes althoughthis trend may be changing.

Exemplary magnetic or magnetizable particles comprise either steel oriron with the iron content as high as about 99% by weight such as thesteel and iron powders used in powdered metallurgy and powder forgingapplications. These particles, however, are quite prone to rustcorrosion notwithstanding the ability of the polymer composition of thisinvention within which they are dispersed to encapsulate them.

For certain applications, particularly where high or potentially highlevels of moisture are of concern, magnetic and/or magnetizableparticles comprised of steel or iron particles encapsulated in a silicaor other corrosion resistant coating comprising a minimum of about 80%iron by weight can be used, notwithstanding a normally higher associatedcost compared to powdered or granular iron or steel.

Magnetic ferrosilicon is somewhat corrosion resistant. Magneticferrosilicon is normally produced in arc furnaces and typical gradescontain between about 15% and about 50% silicon. The silicon inhibitsthe oxidation of the iron such that the particles will not rust. Analternative form of magnetic ferrosilicon is a type that has beenatomized into a more spherical form than conventional crushed and gradedversions. This atomized version tends to mix more readily in thepolymers. It can be beneficial to keep the iron content of theferrosilicon relatively high, with a specific preferred grade comprisingabout 85% iron (about 15% silicon).

When using these above exemplary iron-based magnetic and/or magnetizableparticles, the polymer typically comprises about ¼ to ½ of the totalweight of the composition while iron-based magnetic and/or magnetizableparticles represent the balance ½ to ¾ of the weight of the compositionof the invention. In the Example 1 embodiment, the iron-based magneticand/or magnetizable particles comprise iron and/or the 85% iron grade offerrosilicon and represents about ⅔ of the weight of the composition.

The composition of the invention provides an adhesive floor or wallsurface that has an adhesive effect that is a combination of a magneticattractiveness superimposed upon or combined with a low-tack adhesiveeffect with a surprisingly enhanced shear-resistance adhesive effect inthe horizontal plane in the case of flooring and in the vertical planein the case of vertical surfaces such as walls. The tensile adhesion inthe case of floors is a measurement of a vertical pulling force.Although the following description is based on measurements made in thecase of floor applications, the description also applies to walls.

A method of determining vertical (tensile) adhesion for flooring iscarried out by measuring the force per unit area required to verticallypull (to separate) a magnetic floor covering from the cured surface ofthe composition of the present invention. It is a measurement commonlyknown in the coatings or coverings art as a measure of pull-offstrength. To determine horizontal (shear) adhesion for floor coveringsin the case of the invention, the force per unit area required tohorizontally pull (until there is a visible horizontal shift ormovement) a magnetic floor covering from a cured surface coatingcomprising the adhesive composition of the present invention ismeasured. The shear measurement is especially important for flexiblefloor coverings. Carpets, tiles, rolled vinyl, etc. tend to shift andwrinkle, bunch, pop-up and overlap or otherwise move in undesirable waysif insufficient shear adhesion is present. Although pull-off strengthsare often measured and compared, shear strengths can be a generally moreimportant, albeit less commonly measured property. For an extremeexample illustrating the importance of high shear strengths relative topull-off strengths, a fork lift carrying a load has much less tendencyto lift a floor covering than it does to cause it to shift horizontallywhen applying the brakes or accelerating quickly. A less dramatic butmore common problem is that under high levels of foot traffic, carpetscan shift horizontally in tiny increments with each passing person.Those cumulative shifts can result in relatively large horizontalmovements. Carpets are often pre-stretched and fastened tightly at theedges when being installed to cause them to remain oriented so that anysuch tiny incremental shifts caused by foot traffic or otherwise,relapse after each passing person or other movement. Where there isrelatively high resistance to shear, as is the case when floor coveringsare used with various embodiments of the adhesive coating composition ofthe present invention, there is less or no need to pre-stretch the floorcoverings.

For the tensile pull-off strength test, a 2 inch by 2 inch (50.8 mm×50.8mm) square piece of magnetic floor tile can be used. For the shear test,an 18 inch by 18 inch (457 mm×457 mm) square piece of magnetic floortile can be used. The floor tile for this test comprises a sample of theincreasingly widely used type of flexible floor tile commonly known as“LVT” or “luxury vinyl tile” that has a magnetic backing. This 2 inch by2 inch piece of magnetically-backed LVT has a 15 g mass, exerting about0.15 Newtons (about 0.03 pounds-force) downwards due to its mass. Thelarger 18 inch by 18 inch square magnetically-backed LVT has a 1.42 kgmass, exerting about 14N (about 3 pounds-force) downward due to itsmass. The LVT are each about 3 mm (0.125 inch or ⅛ inch) thick.

Tensile and shear measurements made on various embodiments of thecomposition of the present invention can be compared to cured epoxy,polyurea, polyurethane, polyaspartic and/or other coatings that do nothave any adhesive tack.

COMPARATIVE EXAMPLE

A polyaspartic (polyurea) two part aspartate-ester polyurea (AE-PUREA)composition was used to create a comparative example (non-tack)composition, hereinafter referred to as “Comparative Example”,containing magnetic and/or magnetizable particles comprised ofFerrosilicon Cyclone 60 Atomized Ferrosilicon 15%, containing about 85%iron, available from M&M Alloys, with the ratio of Part A to Part B insaid AE-PUREA being 1.35:1 parts by volume or 100:79 parts by weightwith a typical batch comprising about 4.5 kg (about 10 pounds) of theferrosilicon mixed into about 2.35 liters of the AE-PUREA. A referencetack-free magnetic and/or magnetizable floor coating of the prior art isprepared by curing this Comparative Example composition in a thicknessof about 0.5 mm (0.020 inches). This cured Comparative Examplecomposition has a final hardness greater than about Shore D55.

EXAMPLE 2

An alternative embodiment of a magnetic and/or magnetizable adhesivecoating composition of the present invention, which is a more narrowlyspecified example embodiment of Example 1 and hereinafter referred to asExample 2, comprises a mixture of 177 parts by weight magnetic and/ormagnetizable particles in the form of atomized ferrosilicon, containingabout 85% iron, the same as that used in the Comparative Example; 70parts by weight modified castor oil; and 30 parts by weight polymericMDI is cured in a thickness of about 0.5 mm (about 0.020 inches). Thiscured Example 2 composition has a final hardness less than about ShoreD45.

Vertical tensile and horizontal shear tests performed on this Example 2cured composition are compared to the same tests performed on theComparative Example cured composition. The test results reveal shearenhancements that are disproportionately high in comparison to thevertical tensile pull-off test results. The type and amount of magneticand/or magnetizable particles, as well as the particle density per unitarea, were approximately the same for both.

Some vertical pull-off test results are approximately 120 g (about 1.2Newtons or about 0.26 pounds-force) for the Example 2 embodiment andabout 90 g (about 0.9N or about 0.2 pounds) for the Comparative Example(in both cases measured at 5 minutes). The Example 2 vertical pull-testresult was calculated and found to be 33% higher than the result for theComparative Example. The difference in vertical pull-test result is dueto the additional low-tack adhesion since the magnetic attractiveness isapproximately the same in both.

For additional comparison, the Comparative Example and Example 2, wheninstalled without the inclusion of magnetic and/or magnetizableparticles, gave tensile pull-off strength test results of 0 g (0 Newtonsor 0 pounds-force) and 20 g (about 0.2 Newtons or about 0.05pounds-force) respectively. The difference is entirely due to theadhesive tack properties of Example 2 that are completely lacking in theComparative Example.

The horizontal shear test results are approximately 10 kg (about 98Newtons or about 22 pounds-force) for the Example 2 and about 7 kg(about 69 Newtons or about 15 pounds) for the Comparative Examplerespectively measured, at less than 30 seconds, resulting in a 50%difference. The horizontal shear tests were also zo conducted at 5minutes to yield the results of about 15 kg (about 147 Newtons or about33 pounds) for Example 2 and about 11 kg (about 108 Newtons or about 24pounds) for the Comparative Example, a 40% difference. It is alsonoteworthy that the magnetic attractiveness increases over time due tothe properties of magnetic materials. The magnetic materials tend toalign magnetically when subjected to strong magnetic fields, therebybecoming more magnetically attractive.

While the low tack adhesive properties increase the tensile pull-offnumbers about 30% to 40% over the non-tacky Comparative Example, thecorresponding horizontal shear resistance numbers increase about 40% to50%. Without intending or wanting to be bound to a particular theory,this unexpectedly disproportionately high shear testing result is adesirable one that appears to be caused by the magnetic attractive forceholding the floor covering down to the adhesive compound of theinvention and increasing the frictional resistance as part of thatmagnetic attractive force. It is likely due to the hardness of thepreferred compositions of the invention (under Shore D45) being lowerthan that of the harder non-tacky Comparative Example magnetic coatingcompositions that seem to have in common higher hardness values (overShore D50, more commonly about Shore D60 to Shore D85). The additionalquality of the low-tack adhesive being a softer material appears toallow the floor covering to be pulled down and somehow ‘dig in’ to thecured adhesive more tightly as compared to harder prior art coatingmaterials. This magnetic pulling effect also serves to keep dirt andother contaminants from getting under the coverings during normal useand fouling the system, thereby avoiding prematurely reducing oreliminating low-tack adhesive effect. As was mentioned earlier, low-tackadhesives generally do poorly with floor coverings since such adhesivesare too easily contaminated and too easily lose their adhesive quality.The magnetic attractiveness is largely unaffected by dirt or othercontaminants getting between the covering and magnetic adhesive coatinglayer. Additionally, the relative softness may be aiding the shearresistance by allowing localized imperfections (bumps or raised parts ofthe adhesive coating layer) to become slightly flattened and/orcompressed, thereby increasing the actual physical contact area betweenthe covering and adhesive coating layer more than that which occurs withharder, less-compressible, coatings. Even slight increases in contactarea will allow the low-tack adhesive quality to become more effective.

For additional comparison, the Comparative Example and Example 2, wheninstalled without the inclusion of magnetic and/or magnetizableparticles, gave horizontal shear strength test results of 0 kg (0Newtons or 0 pounds-force) and less than 2 kg (about 20 Newtons or about5 pounds-force) respectively. The difference is entirely due to theadhesive tack properties of Example 2 that are completely lacking in theComparative Example. It is interesting that the low-tack adhesiveproperty in isolation (no magnetic attractiveness aspect) is somewhatsmaller than expected. This appears to be consistent with the abovetheory that without the magnetic attractive force, the tile more easilyseparates or “pops” from the adhesive coating layer since there is noconstant magnetic force increasing the friction between the LVT coveringand adhesive coating layer during the test. The low-tack adhesive aspectdoes not perform nearly as well in isolation as it does when operatingin conjunction with the magnetic attraction aspect. This was anunexpected result. It was expected that the two effects would be simplyadditive, not multiplied as the measurements reveal.

An approximately 2.5 liter mixture of the Example 2 embodiment as wellas a similar amount of the Comparative Reference are easily able to haveabout 4.5 kg (about 10 pounds) respectively of either iron powder withmedian particle size in the range of about 1 to 100 micrometers (about99% iron in the samples used with maximum particle size of about 250micrometers) or the atomized ferrosilicon with median particle sizesmaller on average but still in the same range of about 1 to 100micrometers (about 85% iron in the samples used with maximum particlesize of about 150 micrometers) mixed in easily at ambient temperature.This can be done mechanically using a drill with mixing paddle, by othermechanical means, or by hand using a simple wooden, plastic or metalstir stick, needing no more than a few minutes of mixing time. Suchamount at a coverage rate of about 6.5 square meters or about 70 squarefeet provides for an adhesive coating layer of about 0.5 mm (or about0.020 inches or about 20 mils) thickness that has sufficient magneticattractiveness between the floor covering and cured adhesive coatingcomposition coated substrate floor or wall. A practical minimumthreshold magnetic attractiveness using this above horizontal shearstrength test procedure is at about 10 kg (about 98 Newtons or about 22pounds-force), when tested at about 5 minutes after commencement of thetest. Attempting to stir in a similar amount of magnetite iron oxidepowder (Huntsman-Davis Colors—860 Synthetic Iron Oxide Black™) withpredominant particle size of 0.20 micrometers or 200 nm was notsuccessful because the viscosity increased too much, too soon. Onlyabout half that amount or about 2.5 kg (about 5 pounds) was all thatcould be stirred in manually with ease at ambient temperature. This isgenerally found to be a less than satisfactory amount of the magneticand/or magnetizable magnetite iron oxide particles because thisconcentration generally does not provide for enough magneticattractiveness to keep the floor tiles in place. The horizontal sheartest results were measured at about 5 kg (about 49 Newtons or about 11pounds-force) in this case. However, manufacturing a sheet version ofthe adhesive composition of the invention using elevated temperaturesand a mechanical mixing of high viscosity paste versions enables theinclusion of considerably more dry magnetic and/or magnetizableparticles, such as the magnetite iron oxide particles being describedhere in this example, into the mixture. Similarly, the density of othermagnetic and/or magnetizable particles within various compositions ofthe invention can be increased through such means.

Another feature of the invention is that both the combined total and therelative amounts of adhesion caused by the magnetic attractiveness andlow-tack adhesive can be varied and adjusted to achieve a net effectiveadhesion that meets particular needs for particular applications, whileoptimizing the cost aspects. Varying the low-tack adhesion property isquite inexpensive since it can be done for example in the case ofExample 2, by slightly increasing the ratio of the second component tothe first component from approximately 70:30 parts by weight to 72:28,giving a slightly softer and tackier result. Going in the otherdirection by changing the ratio to 68:32 will yield a harder and lesstacky result. The magnetic attractiveness aspect can be varied byincreasing the amount of magnetic and/or magnetizable particles used inthe composition by mixing more into the composition and/or increasingthe installed thickness. Selecting magnetic and/or magnetizablematerials with greater magnetic properties is another option, althoughgenerally a costly one. Increasing the relative amounts of magneticmaterials or the quality of zo these materials tends to be costly. Themagnetic attractiveness can also be increased by strengthening themagnetic properties of the magnetic backing of the carpet, tiles orother floor or wall coverings through one or more of various knownmeans, also tending again to be more costly than tweaking the adhesivecoating composition formulations.

Exemplary embodiments of the composition have good self-levelingproperties where used in flooring applications and resistance to saggingwhere used in wall applications. The tack properties are low enough thatpersons installing floor coverings are able to walk on the surface ofthe cured composition without their footwear becoming sticky to theextent that such persons are not able to move about freely enough toinstall the floor coverings, without using spiked shoes or otherspecialized footwear.

An exemplary thickness for exemplary embodiments of the curedcomposition is approximately 0.50 mm (about 0.020 inches), with therange of thicknesses being between about 0.20 mm and about 8 mm (about0.008 inches to about 0.30 inches). The good self-leveling properties inthe case of flooring applications for exemplary embodiments of thecomposition allow the composition to fills cracks, voids, dips and lowspots in imperfect floor substrates. The substrates can comprise but arenot limited to concrete and/or other cementitious materials, wood,composite and metal materials.

Field trials with the Example 2 embodiment when compared to theComparative Example showed improved filling of voids, etc. due to thebetter self-leveling properties associated with the Comparative Exampleembodiment. Low spots or voids are highly undesirable under LVT floortiles and other floor coverings, as are bumps, raised areas and/orridges. Such high spots are normally removed mechanically using grindersand/or other means known in the art. Usage where there are voidsunderneath floor coverings such as LVT causes the tiles to begincracking and failing, especially in high traffic areas. This failurebecomes a big problem in applications such as supermarket floors wherevarious trolleys and other wheeled devices carrying loads are frequentlyemployed. The wheels (as well as footwear heels) tend to quickly causesuch depressions or voids under floor tiles to reveal themselves throughdeformation of the tiles. This deformation often causes tiles to fail.Removing any bumps ahead of applying the adhesive coating compositionand allowing the adhesive composition of the present invention to flowinto and fill any such voids prior to installing the floor coveringsreduces or eliminates this problem. There is no limit as to the maximumthickness of the composition where there is such a void although theyare typically no more than about 1 cm (½ inch) in depth. It is commonpractice to fill and level such floors beforehand, selecting from alarge number of commonly available compounds although the composition ofthe present invention also satisfactorily performs this function.

Primers and/or sealers can be used in conjunction with the magneticadhesive coating composition of the present invention. Such primersand/or sealers are normally installed and cured onto the substrate priorto applying the composition, although there are a few that do not needto be fully cured before applying the composition. Such primers andsealers are used to improve adhesion of the composition to the substrateand/or block excess moisture from migrating through the substrate anddegrading the performance of the composition and/or coverings applied tothe cured composition. Various embodiments of the invention can beformulated to have different water vapor transmission rates and moisturevapor permeability properties as needed for various applications. Forinstance, it may be desirable in some situations to have a high moisturevapor permeability to allow moisture to freely migrate and in others tocompletely seal the surface so that little or no moisture can migrate.It may also be desirable in some cases to formulate the composition toseal and prevent radon and/or other toxic gases from migrating.

Foaming the adhesive coating composition of the invention provides forsound and vibration dampening as well as greater cushioning under thefloor or wall coverings. This can be important in areas such asauditoriums or hotels where acoustic properties play an important part.For instance, hotel hallways and rooms often use carpets rather thanvinyl flooring so that there is less noise from footsteps and othersources of sounds and/or vibrations passing between floors and/or walls.

Liquid coatings such as paints, clear varnishes, or sealers can also beused on top of the composition although the low-tack adhesive effectbecomes diminished if there is another coating used on top before themagnetically-backed floor or wall covering is installed. The magneticattractiveness may also become reduced if the top coating is too thick,creating greater distance between the respective magnetically attractedsurfaces.

There may be instances where there is a localized need for an increasein adhesive strength, such as at edges or corners in tile floors. Havingthe composition installed at greater thickness, thereby presenting agreater per unit area density of magnetic and/or magnetizable particlesat the edges aids in this regard. This can also be achieved by applyingsome additional adhesive of a different type to the top of the curedcomposition before placing the magnetically-backed floor (or wall)covering. In cases where it is not desired to use a permanent adhesivefor this, a suitable repositionable adhesive such as one marketed by 3Midentified as Repositionable 75 Spray Adhesive™ may be used. Thisproduct is packaged in aerosol spray cans and comprises about 10% partsby weight of a synthetic elastomer with various solvents and propellants(acetone 30-40%, heptane isomers 20-30%, isobutene 20-30%, propane7-13%). This product is easily spray-applied to the surface of the curedcomposition of the invention.

The composition of the present invention can also be used as part of thefloor or wall covering itself, for example, applied and cured to theunderside of a conventional (non-magnetically-backed) floor tile, eitherin a factory or in the field. Such a tile or covering could bemagnetized using known methods while offering an improvement over priorart magnetically-backed tiles inasmuch as there is an additionallow-tack adhesive property inherent in the adhesive coating composition.Such a low-tack, magnetic covering, when installed on a substrate thathas a cured layer of the adhesive coating composition of the inventionwould in effect provide for an increase in the low-tack adhesive aspectdue to the low-tack adhesive aspect from each respective surface cominginto contact, adding or multiplying the shear adhesion strengths.

Specific examples of compositions, composition components, uses,systems, methods and apparatus have been described herein for purposesof illustration. These are only examples. The technology provided hereincan be applied to zo systems other than the example systems describedabove. Many alterations, modifications, additions, omissions andpermutations are possible within the practice of this invention. Thisinvention includes variations on described embodiments that would beapparent to the skilled addressee, including variations obtained by:replacing features, elements and/or acts with equivalent features,elements and/or acts; mixing and matching of features, elements and/oracts from different embodiments as described herein with features,elements and/or acts of other technology; and/or omitting combiningfeatures, elements and/or acts from described embodiments.

While the invention has been disclosed in its preferred form, thespecific embodiments thereof as disclosed herein are not to beconsidered in a limiting sense, because numerous variations arepossible. The subject matter of the invention includes all novel andnon-obvious combinations and sub-combinations of the various elements,features, functions and/or properties disclosed herein. No singlefeature, function, elements or property of the disclosed embodiments isessential. The following claims define certain combinations andsub-combinations which are regarded as novel and non-obvious. Othercombinations and sub-combinations of features, functions, elementsand/or properties may be claimed through amendment of the present claimsor presentation of new claims in this or a related application. Suchclaims are also regarded as included within the subject matter of thepresent invention irrespective of whether they are broader, narrower orequal in scope to the original claims. This invention also covers allembodiments and all applications which will be immediatelycomprehensible to the expert upon reading this application, on the basisof his or her knowledge and, optionally, simple routine tests. Inaddition, the various embodiments described above can be combined toprovide further embodiments.

It is therefore intended that all claims hereafter introduced areinterpreted to include all such modifications, permutations, additions,omissions and sub-combinations as may reasonably be inferred. The scopeof the claims should not be limited by the preferred embodiments setforth in the examples, but should be given the broadest interpretationconsistent with the description as a whole.

What is claimed is:
 1. A composition comprising: (a) apolyurethane-based adhesive; and (b) magnetic and/or magnetizableparticles mixed into the adhesive, the particles having a minimumdiameter of greater than 100 nm, wherein the adhesive is a two componentadhesive, and wherein said two component adhesive comprises: (i) a firstcomponent comprising a polymerizable isocyanate; and (ii) a secondcomponent comprising glycerides or acylglycerols, wherein the magneticand/or magnetizable particles are mixed in with the second component. 2.The composition as claimed in claim 1, wherein the particles comprisebetween about 30% and about 80% by weight of the total composition. 3.The composition as claimed in claim 2, wherein the particles compriseabout 67% by weight of the total composition.
 4. The composition asclaimed in claim 1, wherein the adhesive is an ambient temperature curedadhesive.
 5. The composition as claimed in claim 1, wherein the adhesiveis a moisture cured adhesive.
 6. The composition as claimed in claim 1,wherein the adhesive is a polymer based adhesive.
 7. The composition asclaimed in claim 1, wherein the adhesive is a hot melt curing adhesive.8. The composition as claimed in claim 1, wherein the adhesive is apressure-sensitive adhesive.
 9. The composition as claimed in claim 1,wherein the glycerides comprise castor oil, the ratio of thepolymerizable isocyanate to the castor oil being between about 20% andabout 45% by weight.
 10. The composition as claimed in claim 1, whereinthe adhesive comprises an elastomer.
 11. The composition as claimed inclaim 1, wherein the particles are comprised of 99% iron.
 12. Thecomposition as claimed in claim 1, wherein the particles are comprisedof 85% iron-containing ferrosilicon.